/*
 * BEEM is a videoconference application on the Android Platform.
 * Copyright (C) 2009 by Frederic-Charles Barthelery,
 * Jean-Manuel Da Silva,
 * Nikita Kozlov,
 * Philippe Lago,
 * Jean Baptiste Vergely,
 * Vincent Veronis.
 * This file is part of BEEM.
 * BEEM is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * BEEM is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with BEEM. If not, see <http://www.gnu.org/licenses/>.
 * Please send bug reports with examples or suggestions to
 * contact@beem-project.com or http://dev.beem-project.com/
 * Epitech, hereby disclaims all copyright interest in the program "Beem"
 * written by Frederic-Charles Barthelery,
 * Jean-Manuel Da Silva,
 * Nikita Kozlov,
 * Philippe Lago,
 * Jean Baptiste Vergely,
 * Vincent Veronis.
 * Nicolas Sadirac, November 26, 2009
 * President of Epitech.
 * Flavien Astraud, November 26, 2009
 * Head of the EIP Laboratory.
 */
package com.beem.project.beem.service;

import org.jivesoftware.smack.Connection;
import org.jivesoftware.smackx.packet.DiscoverInfo;
import org.jivesoftware.smackx.ServiceDiscoveryManager;
import org.jivesoftware.smack.util.PacketParserUtils;
import org.xmlpull.v1.XmlPullParserFactory;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParser;

import android.util.Log;
import java.io.FileReader;
import java.io.Reader;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.Writer;

import java.io.File;
import java.io.IOException;

import android.content.Context;

import com.beem.project.beem.smack.caps.CapsManager;

/**
 * An implementation of CapsManager which keeps DiscoverInfo on the Cache directory of the android application.
 */
public class BeemCapsManager extends CapsManager {

	private static final String TAG = "BeemCapsManager";

	private Context mContext;
	private File mCacheDir;
	private XmlPullParser mParser;

	/**
	 * Create a BeemCapsManager.
	 * 
	 * @param sdm
	 *            the ServiceDiscoveryManager to use
	 * @param conn
	 *            the connection to use
	 * @param context
	 *            the Android context to use to store data
	 */
	public BeemCapsManager(final ServiceDiscoveryManager sdm, final Connection conn, final Context context) {
		super(sdm, conn);
		mContext = context;
		initCacheDirectory();
	}

	@Override
	protected DiscoverInfo load(String ver) {
		File fver = new File(mCacheDir, sanitizeName(ver));
		try {
			Reader fr = new BufferedReader(new FileReader(fver));
			try {
				if (mParser == null) mParser = makeParser();
				mParser.setInput(fr);
				return (DiscoverInfo) PacketParserUtils.parsePacketExtension("query",
						"http://jabber.org/protocol/disco#info", mParser);

			} finally {
				fr.close();
			}
		} catch (Exception e) {
			// The parsePacketExtension throw Exception on error
			Log.d(TAG, "Error while loading Capabilities " + ver, e);
		}
		return null;
	}

	@Override
	protected void store(String ver, DiscoverInfo info) {

		File fver = new File(mCacheDir, sanitizeName(ver));
		try {
			Writer fw = new BufferedWriter(new FileWriter(fver));
			try {
				String data = info.toXML();
				fw.write(data, 0, data.length());
			} finally {
				fw.close();
			}
		} catch (IOException e) {
			Log.d(TAG, "Error while saving Capabilities " + ver, e);
		}
	}

	@Override
	protected boolean isInCache(String ver) {
		boolean result = super.isInCache(ver);
		if (!result) {
			File fver = new File(mCacheDir, sanitizeName(ver));
			result = fver.exists();
		}
		return result;
	}

	/**
	 * Init the cache directory.
	 */
	private void initCacheDirectory() {
		File dir = mContext.getCacheDir();
		mCacheDir = new File(dir, "capabilities");
		mCacheDir.mkdir();
	}

	/**
	 * Make an Xml parser.
	 * 
	 * @return the created xml parser.
	 * @throws XmlPullParserException
	 *             if an error occurs while creating the parser.
	 */
	private XmlPullParser makeParser() throws XmlPullParserException {
		XmlPullParserFactory fact = XmlPullParserFactory.newInstance();
		fact.setNamespaceAware(true);
		return fact.newPullParser();
	}

	/**
	 * Sanitize the base64 ver attribute in order to use it as a filename.
	 * 
	 * @param ver
	 *            the base64 ver attribute
	 * @return a sanitize filename for the ver attribute
	 */
	private String sanitizeName(String ver) {
		return ver.replaceAll("/", ".");
	}
}
